1. Field of the Invention
The instant invention relates to an improved portable chain hoist including a load lifting chain passed over a supporting sprocket therefor and including a pair of depending load supportable ends. Journalled torque input and torque output shafts are provided with the output shaft drivingly coupled to the sprocket and brake structure is operatively associated with the output shaft for braking the latter in both directions of rotation. Torque transfer structure drivingly connects the input shaft to the output shaft through a lost motion connection and is operative to release the brake structure upon the input of rotary torque to the input shaft above a predetermined minimum.
2. Description of Related Art
Various different forms of hoist structures and winch structures provided with automatic brakes as well as other brake structures including some of the general structural and operational features of the instant invention are disclosed in U.S. Pat. Nos. 1,142,908, 1,877,408, 1,942,534, 1,990,163, 1,993,744, 2,569,108, 3,054,597, 3,252,189, 3,333,821 and 3,554,337. However, these previously known structures do not include the overall combination of operational features of the instant invention which result in a portable chain hoist or the like including automatic brake structure as well as a manually operable brake release operable only when the hoist is free of a supported load of any magnitude.